The present disclosure relates to a semiconductor device, and for example to a semiconductor device including a storage device including a plurality of storage elements having a current drawing capability that changes according to a value of data to be stored.
In recent years, nonvolatile memories such as flash memories have been widely used. In such a nonvolatile memory, storage elements having a current drawing capability that changes according to a value of data to be stored are used. Specifically, the storage element changes its current characteristic that is exhibited when the storage element is in an activated state in which the storage element allows a current to flow by its writing operation for data to be held. Then, in a process in which data is read from the storage element, a value of data held in the storage element is determined by reading a magnitude of a drawing current of the storage element. Japanese Unexamined Patent Application Publication No. 2011-165297 discloses an example of a reading circuit for such a storage element.
A nonvolatile semiconductor memory device disclosed in Japanese Unexamined Patent Application Publication No. 2011-165297 includes: a storage element whose electrical-charge discharging speeds of two electrodes change according to logic of stored data; a cell line connected to one of the electrodes of the storage element; a sense amplifier including a sense node connected to the cell line, the sense amplifier being configured to read the logic of data by comparing a potential at the sense node with a reverence potential; and a read control circuit capable of changing its operation between a dynamic sense operation in which reading is performed by pre-charging the cell line and charging or discharging the cell line through the storage element and a static sense operation in which reading is performed in a state where a current load is connected to the sense node.